JPS5896054A - Introduction of methylene into n-phenylcarbamic acid ester - Google Patents

Abstract

PURPOSE:To prepare the bis-compound of the titled compound useful as a starting raw material for the preparation of polyurethane, with little production of by-product, in high selectivity, by reacting an N-phenylcarbamic acid ester with a methylene introducing agent using a specific compound as a catalyst. CONSTITUTION:Methylene group is introduced into an N-phenylcarbamic acid ester of formula (R is alkyl, aromatic group, etc.; R' is H, alkyl, halogen, etc.; r is 0-4, etc.), by reacting the ester with a methylene introducing agent (e.g. formaldehyde, paraformaldehyde, etc.) using a compound having a fluorinated sulfonic acid group of formula CF2SO3H or CFSO3H and a carboxyl group (e.g. difluorosulfoacetic acid, perfluoro-3-sulfopropionic acid, etc.) as a catalyst. The characteristic feature of the catalyst is high rate of reaction and the capability of proceeding the reaction at a temperature of as low as <=100 deg.C.

Description

Detailed Description of the Invention The present invention relates to a method for condensing fd, N-phenylcarbamate ester via a methylene bond.
More details 1-<In other words, the present invention provides N-phenylcarbamate ester'! The present invention relates to an improved method for obtaining a bis form with high selectivity during condensation by reaction with an i Mef V7 agent.

This methylene bis-(4-phenylcarbamate ester) is used as a precursor of 4,4'-diphenylmethane diisocyanate (so-called pure MDI), and this methylene-bis-(4-phenylcarbamate ester),! :, -i (wherein R represents an alkyl group, an aromatic group, or an alicyclic group, and n represents an integer of 1 to 4) A mixture with a polymethylene polyphenyl carbamate ester represented by γ is, So-called Crude MDI
It is a substance useful as a precursor. These incyanates are extremely important industrially as raw materials for polyurethane, and Pure MDI in particular is used for polyurethane elastomer and spandex.

In recent years, demand for it as a coating material for artificial leather, etc., has been decreasing or rapidly increasing. Therefore, it is desired to develop an industrially advantageous method for producing polymethylene polyphenylcarbamate esters containing a large amount of lyulmethylenebis-(4-phenylcarbamate ester), which is a raw material thereof.

Conventionally, the method for producing methylene-bis-(4-phenylcarbamate) using N-phenylcarbamate as a starting material uses formalin, formaldehyde, trioxane, etc. as a condensing agent, and hydrochloric acid, sulfuric acid, phosphorus, etc. A method in which a normal liquid mineral acid such as an acid is used as a catalyst to react in a water bath liquid medium, or an organic sulfonic acid is used as a catalyst!・Methods such as closing and reacting in an organic solvent are known.

However, these methods produce a large amount of side reaction products in addition to the target substance methylene-bis-(4-phenylcarbamate ester), so the yield of the target product is low;
In addition, it has the disadvantage that it takes time and effort to isolate the target product, and is not industrially satisfactory.For example, in the reaction in a water bath using water as a medium, N-phenylcarbamine 8-acid N formed by a reaction at the nitrogen of the ester
-(Alkoxycarbonyl)phenylaminomethylphenyl compounds and N-benzyl compounds such as dimers and trimers of this compound are produced in considerable quantities.

A method using commonly known organic sulfonic acids such as methane, methanesulfonic acid, trifluoromethanesulfonic acid, and halatoluenesulfonic acid as a catalyst (
In JP-A-55-57550), a considerable amount of polymethylene polyphenylcarbamate ester containing three or more benzene rings is used as a substitute, and in both methods, the target substance methylene-bis-(4 - Selectivity to Nisder phenylcarbamate) 0, not very high.

Therefore, the present inventor developed this methylene-bis-(4) with high selectivity.
As a result of intensive studies on a method for obtaining (-phenylcarbamate ester), it was discovered that this object could be achieved by using 1% of a special organic acid, and the invention was completed.

- That is, the present invention -CF, 80. Ht is Isshizuka S
Provided is a method for methylenating N-phenylcarbamate ester, which comprises reacting N-phenylcarbamate ester with a methylenating agent using a compound having a fluorinated sulfonic acid group and a carboxyl group represented by o and H as a catalyst. It's about doing.

The compound used as a catalyst in the present invention has a carboxy group in one molecule, -CF, 80. Ht Taha- and F So
, H as long as it has a fluorinated sulfonic acid group. Such compounds (7) include, for example, difluorosulfoacetic acid, monofluorosulfoacetic acid, monochlorofluorosulfoacetic acid, perfluoro-3-sulfopropionic acid.

3.3'-difluoro-3-sulfopropionic acid, perfluoro-4-sulfobutyric acid, perfluoro-5=sulfopentane, perfluoro-6-sulfohexanoic acid, sulfodifluoromethylbenzoic acid, and the like are used. Of course, in these compounds, fluorine or hydrogen may be substituted with a lower perfluoroalkyl group. Particularly preferred is difluorosulfoacetic acid (HOOCCF, 80
．． H) and perfluoro-3-sulfopropionic acid (I-100ccF, CF.

80, )(). These compounds are 1fIt! as catalysts! Or used by 2 gentlemen or above. The method for producing 11"J of such compounds is not particularly defined, and any method may be used. For example, perfluorosultones are hydrolyzed with an alkali.
After that, the generated salt is acidified, or the sultone is hydrolyzed with a compound ke-alkali prepared by electrolytic fluorination, and then ionta exchanged by tilting.
H (n = an integer of 2 or more) Tetrafluoroethylene is reacted with thioalcolade and dimethyl carbonate to produce a compound containing a thioether group and an ester group, which is then subjected to hydrolysis, oxidation, alkaline hydrolysis, and ion exchange with acid. The method via C2H5SNa +CFz=CF2 +(CH30)2
CO-→(4H5SCF2CF2CO2CH3+ C
H30NBC2H5SCF2CF2Co2CH3+H2
゜-)C2H5SCF2CF2CO2H+ CH30H
C2H,5CF2CF1CO2H1c2H5802CF
2CF, C02H alkali--p Na 03 S CF2 CFz CO2
After alkaline hydrolysis of the reaction product of H tetrafluoroethylene and chlorosulfonyl fluoride or trichloromethylsulfonyl fluoride.

Method of ion exchange with acid, below margin 2 CF2=CF2 +C15O2F-MishiCt(CF
2) 4So□F-)Na02C(CF2)B
803 Na −+'f(01C(CF@) 38
03 H20F2=CF, + CCt3so2F→C
1a C(CF2) 4802 F->Na02C
(CF2)45O1Na →HO2C(CF2)4SO
There are 3B etc.

In the method of the present invention, a carboxyl group and -
When N-phenylcarbamate is reacted with a menalenating agent by using a compound having a fluorinated sulfonic acid group represented by CF2SO3H or -CFSO3'H as a catalyst, methylenation is obtained at the 44'-position. Although it is not clear why methylene-bis-(4-phenylcarbamine ester) can be obtained with a higher selectivity compared to the case of using a normal state and sulfonic acid, Strong+'N! It is concluded that the coexistence of two sulfonic acid groups in the molecule determines the methylenation position of 151ψ in the phenyl group of the N-phenylcarbamate ester. In addition, since the catalytic acid used in the present invention has a very 11M1 acidic group called a fluorinated sulfonic acid group, the reaction rate is fast and the reaction proceeds even at low flow rates below 100°C. - It also has the characteristic that it hardly generates a compound in which the nitrogen of phenylcarbamate is methylenated.

N-phenylcarbamate t- used in the present invention
1゛, a compound represented by the general formula, where R represents an alkyl group, an aromatic group, or an alicyclic group, and R'6゛hydrogen or alkyl crab, halogen atom, nitro group, cyan group, 114% groups such as alkoxy groups and sebaceous groups, these @ extension groups are bonded to the ortho or meta position with the urethane group VCt=i, and ril' is an integer of 0 to 4. Was. Further, when r is 2 or more, R' may be the same or may be a different envy "'Ilj 7+!".

Furthermore, RIrJ that one or more water, :・ is Ail n
It may be substituted with V by the +- group of b.

In this more specific N-phenylcarbamine W ester, R is a methyl group, ethyl M is 2,2.2-trichloroethyl group, 2.2.2
-) Lifluoroethyl group, globyl group (n-, iso
→, butyl k (n- and each conjugate), pentyl group (
n- and various isomers), hexyl group (n- and each f!I
! isomers), or cyclopentyl groups,
Cyclohexyl radicals are any 1i1i buried group base, also d phenyl λ, naphthyl, etc. aromatic noi (, R/ is water 'J'1.
; or an alicyclic 1jj-7'41- or -j halogen atom such as fluorine, chlorine, bromine, iodine, a nitro group, a cyano group, or an alkoxy group containing an alkyl no of jiDelf, etc.; N is better than that
- Phenylcarbamine resistance? Examples include esters.

Preferred ki, methyl N-phenylcarbamate, N
-Ethyl phenylcarbamate, N-phenylcarbamine@',; n-Flovir, N-phenylcarbamine l:'# 180-Flovir, 'N-phenylcarbaminvn-butyl, I'VJ-phenylcarbamate 5ec-butyl , N-phenylcarbamic acid iso-
Butyl, tert N-phenylcarbamate, -butyl, pentyl N-phenylcarbamate, hegysyl N-phenylcarbamate, N-phenylcarbamine 111.
Cyclohexyl, N-phenylcarbamic acid 2.2.2
-Trichloroethyl, N-phenylcarbamine jib
2,2.2-trifluoroethyl, N-o or In=methyl tolylcarbamate, N-o5/il',
m-tolylcarbamine 1i ethyl, N-o or i1'
m -) Lylcarbamine 2,2.2-trifluoroethyl, N-o or i, tm -) Lylcarbamine propyl (famous species soft), N'-0 or 1rJ'rn-) I
Butyl J-carbamate (% 14 soft), N-
o Nuke m-chlorophenylcarbamine 111□, methyl, N-o or dm-chlorophenylcarbamate ethyl,
Propyl N-o or m-chlorophenylcarbamate (
Each j[JF), N-0 or m-chlorphenylcarbamine enemy phthyl (nominal isomerism %:), N-0 or m-chlorphenyl force #A minfi? 2,2.2-trifluoroethyl, N-2゜6-dimethylphenylcarbamic acid methyl, N-2,6-dimethylphenylcarbamic acid ethyl, N-Z, 6-/methylphenylcarbamate furovir ( (each isomer), butyl N-2,6-dimethylcarbamate (each isomer), 2,2.2-)lifluoroethyl N-2,6-dimethylcarbamate, N-
Methyl 2,6-dibromphenylcarbamate, N-2
, 6-dibromphenylcarhamine fr& -[-f, N-2゜propyl 6-dibromphenylcarbamate (each isomer), methyl N-216-dibromphenylcarbamate (each isomer), N -2,6-Dibromphenylcarbamic acid 2,2.2-) N-phenylcarbamine such as IJ fluoroethyl! r! Used by Soe Nuterna.

Examples of the methylenating agent used in the present invention include formaldehyde, paraformaldehyde, trioxane, tetraoxane, dialkoxymethane, cyasyloxymethane, 1,3-dioxolane, 1,3-dioxane, 1,3
-dithiane, 1,3-oxathiane, hexamethylenetetramine, etc. are used, but among the methylenated compounds of J't et al., the preferred ones are formaldehyde, paraformaldehyde, trioxane, and those having 1 to 6 carbon atoms. (Dialkoxymethane having lj-class alkyl group, ita-11o is lower carboxyl such as jetoxymethane, jetoxymethane, dipropoxymethane, dipentoxymethane, dihexyloxymethane, dialkoxymethane, dialkoxymethane, etc.) These include siasiloxymethane having a group, and these may be used alone or in combination of two or more.

This defense law] No gamma? Although it can be carried out with one solvent, it can also be carried out with a suitable solvent if necessary. Examples of such solvents include pentane, hexane, heptane,
Octane, nonane, decane, n-hexatecane, cyclopentane, cyclohexyl group fatty acids are alicyclic hydrocarbons, chloroform, enriched methylene, carbon tetrachloride,
Haloconated hydrocarbons such as dichloroethane, trichloroethane, and tetrachloroethane; alcohols such as methanol, ethanol, propatool, and butanol;
, benzene, toluene, xylene, ethylbenzene, monochrono) 2benzene, dichloro-, 10-benzene, romnaphthalene, nitrobenzene, o-'>7. iJ:m
-Aromatic compounds such as 1Jp-nitrotoluene,
Ethers such as diethyl ether, l,4-dimegysan, and tetrahydrofuran, esters such as acid-resistant ethyl, ethyl acetate, and dimethyl 5, sulfolanes such as sulfolane, 3-methylsulfolane, and 2,4-dimethylsulfolane, l'H, IM? , propion 1γ1
1 Monochloroacetic acid, monochloroacetic acid, trichloroacetic acid
, trifluoro! Carboxylic acids such as ij1, sulfonic acids such as methanesulfonic acid, trichloromethanesulfone I*, trifluoromethanesulfonic acid, and water are used.

In carrying out the method of the present invention, the molar ratio of the methylenating agent and the N-phenylcarbamine liquid ester is controlled appropriately.
Although there is no t-1, it is more preferable to use the methylenating agent in the range of 0.01 to 10 mol per 1 mol of N-phenylcarbamine ρ ester. 1$: 0
．． 1. If the amount of methylenating agent used is small, the residual rate of unmeasured N-phenylcarbamine ester will increase, and if JJ1 is greater than The proportion of polymethylene polyphenylcarbamine monoester formed in the nuclear body increases as the age increases.

There is no particular restriction on the amount of catalyst used, but it is usually N-phenylcarbamine 1'! 10-5 per mole of ester
~io mole per mole, more preferably 1 mol per 1 O-4 to 1 mole per mole.

As a method for separating the compound of the present invention from the reaction product, for example, extraction with an alkaline water bath solution, distillation, etc. can be used, and it can be easily separated. It can be recovered.

The reaction temperature of non-exposure and brightness is below 250℃, preferably 10-20℃.
0℃? i; 1 degree, but a more preferable temperature is 50 to 180 degrees Celsius. It is surrounded.

゛Is the method of the present invention usually carried out in a normal pressure press or not? [It can also be carried out under reduced pressure if required.

1. Reaction temperature, meter, addition of medium and box, presence of medium! ! Depending on other reaction conditions such as 1 and 1, concentration, reaction method, etc., the reaction time may be y.times.1 or approximately 1 to several hours.

It's a moat, the reaction method of Dou Invention is 9. ! 3 is not limited, and may be a batch type, continuous type, semi-continuous type, etc., and the reaction apparatus is not particularly limited either.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. The analysis of the reaction product (1) was mainly carried out using high performance liquid chromatography.

Example I Ethyl N-phenylcarbamate 16.5 t,)
rioxane if, perfluoro-3-sulfopropionic acid 1.2 f, p-nitrotorbone 30 ml so m
e Ladder: Place in a stirred autoclave and heat at 120°C for 1 hour.
11 reactions were performed. Analysis of the reaction solution showed that the reaction rate of ethyl N-phenylcarbamate was 40%, and the selectivity of methylene-bis-(4-phenylcarbamate ethyl) was 77%.
%Met. The selectivity of 2,4'-methylene di(phenylcarbamin ethyl) was 10%, and the remainder was polymethylene polyphenylcarbamin 1 ethyl having a d3 nucleus or more.

Example 2 Implementation 1'11 using methyl N-phenylcarbamate 15.1F, dimethoxymethane 1.9F, perfluoro-3-sulfopropion IR, sulfolane 30-
(As a result, the reaction rate of N-food d% rubamine pk methyl was 38%, and methylene-bis-(4
- methyl phenylcarbamate) selectivity Huff 5%,
It was found that the selectivity for 2.4'-methylene-di(methyl phenylcarbamate) was 14%, and the remainder was polymethylene polyphenylmethylcarbamate.

Example 3 N-phenylcarbaminteethyl 16.5 ? , jetoxymethane 2.6? , difluorosulfonic acid [112o
, 92, by the same method as in Example 1 using 30 ml of nitrobenzene at 110° C. for 2 hours. , let. Analysis of the reaction solution '14&:j:, The reaction rate of ethyl N-phenylcarbamate was 52%, and methylene-bis-(4-
The selectivity of phenylcarbamine (ethyl) is 80%,
The selectivity of polymethine/polyphenylcarbamate enal was 11%.

Example 4 N-phenylcarbamine #n-butyl 9.6F.

Using 0.5F of paraformaldehyde, 0.5F of difluorosulfoacetic acid, and 40% acetic acid, the same reaction mixture as in Example 1 was reacted in an autoclave at 120°C for 1 hour. As a result of analyzing the reaction solution, the reaction rate of n-butyl N-phenylcarbamate was 53%, the selectivity of methylene-bis-(4-phenylcarbamine good butyl) was 78%, and the reaction rate of n-butyl N-phenylcarbamate was 78%. The selection rate is 13%
Met.

Example 5 A sulfolane clear liquid containing 15-4 F% of ethyl N-phenylcarbamate, 1 weight of trioxane, and 1 weight of perfluoro-3-sulfopropion was kept at 130°C in a tube with an inner diameter of 4 mm and a length of 2 m. 20m in stainless steel reaction tube
It was injected at a rate of e/hr.

This reaction tube has VC length of 20o at 20m intervals? It is a combination of five static mixers and a vent-shaped pipe, and is held horizontally. When the steady state was reached, the product solution was analyzed and the reaction rate of ethyl N-phenylcarbamate was 38%, and the selectivity of methylene-bis-(ethyl 4-phenylcarbamate) was %. So, 2.4
The selectivity for ethyl '-methylene di(phenylcarbamate) was 8%, and the selectivity for ethyl polymethylene polyphenylcarbamate was 12%.

Example 6 Perfluoro-4-sulfobutyric acid 2f as catalyst/+IJ
.

In Example 1, the reaction was carried out in exactly the same manner as in Example 1 using sulfola Y30 td as a reagent. The reaction rate of ethyl N-phenylcarbamate was 48%, It was found that polymethylene polyphenylcarbamic acid was produced with a selectivity of 10% and a selectivity of 79% for ethyl acid) V, 1.

Claims (1)

[Claims] A method characterized by reacting N-phenylcarbamate with a methylenating agent using a compound having a fluorinated sulfonic acid group and a carboxyl group represented by t-CF2So,H or -CFSO,H as a catalyst. Method 2 for methylenation of N-phenyl rubbery/monoesters, the catalyst is difluorosulfoacetic acid (HOOCCF,
So, H) and/or Perflu'rho3 sulfopropionic acid (HOOCCF2CF280.H).